General considerations of the cosmological constant and the stabilization of moduli in the brane-world picture

TL;DR

This paper discusses how brane-world models impact the cosmological constant problem and explores the challenges in stabilizing moduli fields, proposing damping mechanisms for their slow evolution.

Contribution

It demonstrates that brane-world setups restrict arbitrary cosmological constant additions and suggests cosmological damping as a solution for moduli stabilization.

Findings

Adding an arbitrary constant to the effective theory is disallowed in brane-world models.

Stabilizing moduli fields is challenging due to their dynamics.

Damping mechanisms can slow moduli evolution, aiding stabilization.

Abstract

We argue that the brane-world picture with matter-fields confined to 4-d domain walls and with gravitational interactions across the bulk disallows adding an arbitrary constant to the low-energy, 4-d effective theory -- which finesses the usual cosmological constant problem. The analysis also points to difficulties in stabilizing moduli fields; as an alternative, we suggest scenarios in which the moduli motion is heavily damped by various cosmological mechanisms and varying ultra-slowly with time.